The present invention relates in general to an optical detector or sensor which is utilized in a seeker system for tracking a target.
The use of laser light to illuminate a target to read the position of the target is well known in the art. A laser light detector may be utilized with suitable optics provided for this purpose. It is also known to use other portions of the electromagnetic spectrum, specifically the light and near light portions of the spectrum, to detect and track a target. Videocameras for example can be utilized under good visibility conditions. Under poor visibility conditions the infrared portion of the electromagnetic spectrum can be utilized for this purpose.
An acceptable seeker system thus must operate over a wide wavelength spectrum to accommodate various target signatures and atmospheric transmission effects and conditions. Various seeker systems which are sensitive to specific wavelength ranges must be used with suitably provided detectors for the various wavelength ranges.
Prior embodiments of such overall sensor systems employed dual optical systems with completely separate detectors and processing elements. It is also known to use a single set of optics which transmit all of the wavelength regions of interest. A wavelength selective element is utilized for dividing the light into the various wavelength ranges. Such an element is a dichroic mirror.
For certain applications the completely separate optical/detector configuration may not be compatible with available space requirements. Such prior art systems are wasteful of volume and weight and relatively expensive due to the large number of optical elements required. The use of wavelength selective elements was an attempt at reducing such volume and weight requirements by reducing the number of optical elements required. The various wavelength bands were separated out and directed to discrete detector elements. This configuration however only partially solves the basic problem in that still two completely separate optical paths after wavelength separation are required.
A suitable optical system is needed which passes all wavelength regions of interest, including such as a laser detector configuration which detect one wave-length region (in the area of 1.06 micrometers) and which can transmit other wavelength regions of interest, for example the wavelength region between 3.0 and 15.0 micrometers, such as having an infrared detector which is useful in the 3.0 to 15.0 micrometer region with corresponding nutation assembly including movable reticle.